Use the native "struct iovec" as our "struct evbuffer_iovec" when available, so we do not need to copy more pointers than necessary.

svn:r1299

buffer.c

@@ -1475,17 +1475,10 @@ _evbuffer_expand_fast(struct evbuffer *buf, size_t datlen)
 #define IOV_PTR_FIELD buf
 #define IOV_LEN_FIELD len
 #endif
-
-#define IOV_TYPE_FROM_EVBUFFER_IOV(i,ei) do {		\
-		(i)->IOV_PTR_FIELD = (ei)->iov_base;	\
-		(i)->IOV_LEN_FIELD = (ei)->iov_len;	\
-	} while(0)
-
 #endif
 
 #define EVBUFFER_MAX_READ	4096
 
-#ifdef USE_IOVEC_IMPL
 /** Helper function to figure out which space to use for reading data into
     an evbuffer.  Internal use only.
 
@@ -1494,7 +1487,8 @@ _evbuffer_expand_fast(struct evbuffer *buf, size_t datlen)
     @param vecs An array of two iovecs or WSABUFs.
     @param chainp A pointer to a variable to hold the first chain we're
       reading into.
-    @param exact DOCDOC
+    @param exact Boolean: if true, we do not provide more than 'howmuch'
+      space in the vectors, even if more space is available.
     @return The number of buffers we're using.
  */
 int
@@ -1546,7 +1540,6 @@ _evbuffer_read_setup_vecs(struct evbuffer *buf, ssize_t howmuch,
 	*chainp = chain;
 	return nvecs;
 }
-#endif
 
 /* TODO(niels): should this function return ssize_t and take ssize_t
  * as howmuch? */
@@ -1605,16 +1598,23 @@ evbuffer_read(struct evbuffer *buf, evutil_socket_t fd, int howmuch)
                 goto done;
 	} else {
 		IOV_TYPE vecs[2];
+#ifdef _EVBUFFER_IOVEC_IS_NATIVE
+		nvecs = _evbuffer_read_setup_vecs(buf, howmuch, vecs,
+		    &chain, 1);
+#else
+		/* We aren't using the native struct iovec.  Therefore,
+		   we are on win32. */
 		struct evbuffer_iovec ev_vecs[2];
 		nvecs = _evbuffer_read_setup_vecs(buf, howmuch, ev_vecs,
 		    &chain, 1);
 
 		if (nvecs == 2) {
-			IOV_TYPE_FROM_EVBUFFER_IOV(&vecs[1], &ev_vecs[1]);
+			WSABUF_FROM_EVBUFFER_IOV(&vecs[1], &ev_vecs[1]);
-			IOV_TYPE_FROM_EVBUFFER_IOV(&vecs[0], &ev_vecs[0]);
+			WSABUF_FROM_EVBUFFER_IOV(&vecs[0], &ev_vecs[0]);
 		} else if (nvecs == 1) {
-			IOV_TYPE_FROM_EVBUFFER_IOV(&vecs[0], &ev_vecs[0]);
+			WSABUF_FROM_EVBUFFER_IOV(&vecs[0], &ev_vecs[0]);
 		}
+#endif
 
 #ifdef WIN32
 		{

buffer_iocp.c

@@ -245,11 +245,6 @@ done:
 	return r;
 }
 
-#define IOV_TYPE_FROM_EVBUFFER_IOV(i,ei) do {		\
-		(i)->buf = (ei)->iov_base;		\
-		(i)->len = (ei)->iov_len;		\
-	} while(0)
-
 int
 evbuffer_launch_read(struct evbuffer *buf, size_t at_most)
 {
@@ -280,7 +275,7 @@ evbuffer_launch_read(struct evbuffer *buf, size_t at_most)
 	nvecs = _evbuffer_read_setup_vecs(buf, at_most,
 	    vecs, &chain, 1);
 	for (i=0;i<nvecs;++i) {
-		IOV_TYPE_FROM_EVBUFFER_IOV(
+		WSABUF_FROM_EVBUFFER_IOV(
 			&buf_o->read_info.buffers[i],
 			&vecs[i]);
 	}

evbuffer-internal.h

@@ -252,6 +252,7 @@ void _evbuffer_chain_unpin(struct evbuffer_chain *chain, unsigned flag);
 /** As evbuffer_free, but requires that we hold a lock on the buffer, and
  * releases the lock before freeing it and the buffer. */
 void _evbuffer_decref_and_unlock(struct evbuffer *buffer);
+
 /** As evbuffer_expand, but does not guarantee that the newly allocated memory
  * is contiguous.  Instead, it may be split across two chunks. */
 int _evbuffer_expand_fast(struct evbuffer *, size_t);
@@ -265,6 +266,12 @@ int _evbuffer_expand_fast(struct evbuffer *, size_t);
 int _evbuffer_read_setup_vecs(struct evbuffer *buf, ssize_t howmuch,
     struct evbuffer_iovec *vecs, struct evbuffer_chain **chainp, int exact);
 
+/* Helper macro: copies an evbuffer_iovec in ei to a win32 WSABUF in i. */
+#define WSABUF_FROM_EVBUFFER_IOV(i,ei) do {		\
+		(i)->buf = (ei)->iov_base;		\
+		(i)->len = (ei)->iov_len;		\
+	} while(0)
+
 #ifdef __cplusplus
 }
 #endif

include/event2/buffer.h

@@ -70,6 +70,9 @@ extern "C" {
 #ifdef _EVENT_HAVE_SYS_TYPES_H
 #include <sys/types.h>
 #endif
+#ifdef _EVENT_HAVE_SYS_UIO_H
+#include <sys/uio.h>
+#endif
 #include <event2/util.h>
 
 struct evbuffer;
@@ -94,12 +97,18 @@ struct evbuffer_ptr {
 
     @see evbuffer_reserve_space, evbuffer_commit_space, evbuffer_peek
  */
+#ifdef _EVENT_HAVE_SYS_UIO_H
+#define evbuffer_iovec iovec
+/* Internal use -- defined only if we are using the native struct iovec */
+#define _EVBUFFER_IOVEC_IS_NATIVE
+#else
 struct evbuffer_iovec {
 	/** The start of the extent of memory. */
 	void *iov_base;
 	/** The length of the extent of memory. */
 	size_t iov_len;
 };
+#endif
 
 /**
   Allocate storage for a new evbuffer.